Our cross-platform fintech app is live on both iOS and Android, but stability and feature gaps are holding us back. Recent crash logs from Xcode and Android Studio point to memory leaks and unhandled promises; at the same time, card-on-file payments occasionally fail at the gateway hand-off. Screens that list transactions feel noticeably sluggish on mid-tier devices. I need these core issues resolved and a few key features tightened up so we can ship the next release with confidence. Scope of work • Debug and eliminate all recurring crashes on iOS and Android, submitting test builds through TestFlight and internal Play tracks for verification. • Fix payment integration issues end-to-end, including proper error handling and graceful fallbacks. Stripe is already wired up in the Java (Spring Boot) API, so most changes will be React Native side with light API tweaks if required. • Profile, optimise, and benchmark slow screens—especially the transaction history list—using native profilers, Hermes, and Flipper. Target <1 s initial load on devices running Android 10 and iOS 14 or newer. • Polish and extend user authentication: add biometric fallback, tighten token refresh logic, and surface clearer error states. • Rework the transaction history component with server-side pagination and pull-to-refresh. • Implement reliable push and in-app notifications via Firebase Cloud Messaging, tying into the existing Next.js frontend for web alerts. Tech environment React Native (0.72), TypeScript, Redux Toolkit, Java/Spring Boot REST API, PostgreSQL, Next.js (13) for the web portal, Firebase for messaging, and GitHub Actions for CI/CD. Deliverable acceptance 1. Crash-free builds passing QA regression on both stores. 2. Successful test payments in sandbox and live mode across three different card brands. 3. Profiling report showing improved frame times and network payload reductions. 4. Auth, transaction, and notification features fully covered by unit and e2e tests (Jest + Detox). Clear, well-commented PRs through our GitHub flow are a must; I’ll review and merge once each acceptance item is met.